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| United States Patent |
5,571,585
|
|
Yoshida
, et al.
|
November 5, 1996
|
Resin-coated pipe
Abstract
Disclosed is a resin-coated pipe, which is obtainable by extrusion coating
a tubular base with a resin composition comprising 5 to 30% by weight of a
component A and 95 to 70 by weight of a component B. Component A: an
ethylene-.alpha.-olefin copolymer resin in which the melt flow rate at a
temperature of 190.degree. C. and under a load of 2.16 kg is 0.01 to 50 g
per 10 min., the density is 0.910 g/cm.sup.3 or below, and the maximum
fusion peak temperature as measured by a differential scanning calorimeter
is 60.degree. C. or above. Component B: crystalline polypropylene, in
which the melt flow rate at a temperature of 190.degree. C. and under a
load of 2.16 kg is 0.1 to 10 g per 10 min. The resin-coated pipe, using
the above resin composition which is excellent in processibility, is
excellent in the mechanical strength, normal and low temperature impact
resistance, heat resistance, chipping resistance and coating surface
appearance.
| Inventors:
|
Yoshida; Jiichirou (Ichihara, JP);
Nezu; Syoich (Chiba, JP);
Ono; Junichi (Okazaki, JP)
|
| Assignee:
|
Sumitomo Chemical Company Limited (Osaka, JP)
|
| Appl. No.:
|
364499 |
| Filed:
|
December 27, 1994 |
Foreign Application Priority Data
| Current U.S. Class: |
428/36.91; 138/140; 138/143; 138/145 |
| Intern'l Class: |
B32B 015/08 |
| Field of Search: |
428/36.91
138/143,140,145
|
References Cited
U.S. Patent Documents
| 3967020 | Jun., 1976 | Uemura et al. | 428/36.
|
| 4071048 | Jan., 1978 | Watase | 138/145.
|
| Foreign Patent Documents |
| 52-95759 | Aug., 1977 | JP.
| |
| 61-255952 | Nov., 1986 | JP.
| |
| 66653 | Jan., 1994 | JP.
| |
| WO9003850 | Apr., 1980 | WO.
| |
| WO9012657 | Nov., 1990 | WO.
| |
Primary Examiner: Nold; Charles
Attorney, Agent or Firm: Sughrue, Mion, Zinn, Macpeak & Seas
Claims
What is claimed is:
1. A resin-coated pipe obtainable by extrusion coating a tubular base with
a resin composition comprising 5 to 30% by weight of a component A as
shown below and 95 to 70% by weight of a component B as shown below:
Component A: an ethylene-.alpha.-olefin copolymer resin in which the melt
flow rate at a temperature of 190.degree. C. and under a load of 2.16 kg
is 0.01 to 50 g per 10 min., the density is 0.910 g/cm or below, and the
maximum fusion peak temperature as measured by a differential scanning
calorimeter is 60.degree. C. or above;
Component B: a block copolymer containing propylene and up to 15% by weight
.alpha.-olefin having a carbon number of 2 or of 4 to 10, in which the
melt flow rate at a temperature of 190.degree. C. and under a load of 2.16
kg is 0.1 to 10 g per 10 min.
2. The resin-coated pipe according to claim 1, wherein regarding to said
component A, the melt flow rate at a temperature of 190.degree. C. and
under a load of 2.16 kg is 0.2 to 50 g per 10 min., and the maximum fusion
peak temperature as measured by a differential scanning calorimeter is
100.degree. C. or above.
3. The resin-coated pipe according to claim 1, wherein regarding to said
component A, the density is 0.860 to 0.910 g/cm.sup.3, the maximum fusion
peak temperature as measured by a differential scanning calorimeter is
60.degree. to 120.degree. C., and the ratio of the weight-average
molecular weight to the number-average molecular weight as measured by GPC
method is 1.5 to 3.0.
4. The resin-coated pipe according to claim 1, wherein .alpha.-olefin in
said component A is .alpha.-olefin having a carbon number of 3 to 12.
5. The resin-coated pipe according to claim 1, wherein the resin coating
has a thickness of 0.3 to 2 mm.
6. The resin coated pipe according to claim 1, wherein the tubular base is
a steel pipe.
Description
BACKGROUND OF THE INVENTION
This invention relates to a resin-coated pipe and, more particularly, to a
resin-coated pipe, which has a resin composition excellent in the
processibility and is excellent in the mechanical strength, impact
resistance at normal and low temperatures, heat resistance, chipping
resistance and coating surface appearance.
Resin layers for resin-coated pipes are generally required to be excellent
in the mechanical strength, impact resistance at normal and low
temperatures, heat resistance, chipping resistance and coating surface
appearance and also excellent in the processibility.
Heretofore, polyethylene obtained by high pressure process and
ethylene-vinyl acetate copolymer have been used as a resin layer for
resin-coated pipes. These materials, however, are inferior in the chipping
resistance. The chipping resistance is a very important property in view
of the protection of pipes, particularly steel pipes, used in outdoor
places exposed to small stones or the like flying thereto. Coating resins
which are obtainable by cross-linking high pressure process polyethylene
or ethylene-vinyl acetate copolymer with peroxides or through electron
beam irradiation are comparatively satisfactory in the chipping
resistance. These resins, however, require a separate step of thermal
shrinking at the time of coating the steel pipe. The coating process is
therefore time-consuming, and thus the mass productivity is inferior.
SUMMARY OF THE INVENTION
In view of the above situation, it is an object of the invention to provide
a resin-coated pipe, which has a resin composition excellent in the
processibility and is excellent in the mechanical strength, impact
resistance at normal and low temperatures, heat resistance, chipping
resistance, and coating surface appearance.
According to the invention, there is provided a resin-coated pipe
obtainable by extrusion coating a tubular base with a resin composition
comprising 5 to 30% by weight of a component A as shown below and 95 to
70% by weight of a component B as shown below:
Component A: an ethylene-.alpha.-olefin copolymer resin, in which the melt
flow rate at a temperature of 190.degree. C. and under a load of 2.16 kg
is 0.01 to 50 g per 10 min., the density is 0.910 g/cm.sup.3 or below, and
the maximum fusion peak temperature as measured by a differential scanning
calorimeter is 60.degree. C. or above.
Component B: crystalline polypropylene, in which the melt flow rate at a
temperature of 190.degree. C. and under a load of 2.16 kg is 0.1 to 10 g
per 10 min.
DETAILED DESCRIPTION OF THE INVENTION
With the component A according to the invention, the melt flow rate at a
temperature of 190.degree. C. and under a load of 2.16 kg is 0.01 to 50 g
per 10 min. If this melt flow rate is insufficient, it results in inferior
processibility. If the rate is excessive, it results in inferior
mechanical strength.
With the component A according to the invention, the density is 0.910
g/cm.sup.3 or below. If the density is excessive, it results in inferior
impact resistance at low temperatures.
With the component A according to the invention, the maximum fusion peak
temperature as measured by a differential scanning calorimeter is
60.degree. C. or above. If this temperature is insufficient, it results in
inferior heat resistance.
In the component A according to the invention, .alpha.-olefin preferably
has a carbon number of 3 to 12, more preferably a carbon number of 3 to
10. Examples of .alpha.-olefin are propylene, butene-1, 4-methylpentene-1,
hexene-1, octene-1, decene-1, etc. These .alpha.-olefins may be used alone
or in combinations. The .alpha.-olefin content in the component A is
usually 1 to 30% by weight.
While the component A according to the invention is as shown above, more
preferred embodiments of carrying out the invention may be given depending
on the use of the resin-coated pipe as the object of the invention.
In one such preferred embodiment, the component A, which has the above
requirements, is such that the melt flow rate at a temperature of
190.degree. C. and under a load of 2.16 kg is 0.2 to 50 g per 10 min. and
that its maximum fusion peak temperature as measured by a differential
scanning calorimeter is 100.degree. C. or above.
If the melt flow rate at a temperature of 190.degree. C. and under a load
of 2.16 kg is less than 0.2, the processibility may be insufficient.
If the maximum fusion peak temperature as measured by a differential
scanning calorimeter is less than 100.degree. C., the heat resistance is
insufficient.
As a method of obtaining the above preferred component A, mention may be
made of a method, in which ethylene and .alpha.-olefin are polymerized in
the presence of a Ziegler type catalyst.
The polymerization is carried out at a normal polymerization temperature of
30.degree. to 300.degree. C., under a normal pressure to 3,000
kg/cm.sup.2, in the presence or absence of catalyst and in a gas-solid,
liquid-solid or homogeneous liquid phase. Further, the polymerization is
preferably carried out in a high pressure bulk process at a polymerization
temperature of 130.degree. to 300.degree. C. and under a polymerization
pressure of 300 to 3,000 kg/cm.sup.2.
The Ziegler type catalyst is preferably composed of a compound of a
transition metal element in Group IVb and/or Vb of the periodic table of
elements and a compound of a metal element in Group IIb and/or IIIa of the
periodic table. Examples of the transition metal element compound are
halides, alkoxides and the like with of titanium, zirconium, hafnium,
vanadium, etc. Further, it is possible to suitably use a composite
compound composed of such transition metal element compound and a halide
of a typical metal in Group IIa and/or IIIa of the periodic table, such as
magnesium chloride, aluminum chloride, etc. As the compound of a metal
element in Group IIb and/or IIIa of the periodic table may suitably be
used hydrides and/or organic metal compounds of zinc and/or aluminum.
Examples of the Ziegler type catalyst are those disclosed in Japanese
Patent Laid-open Publication No. Sho 49-97088, Japanese Patent Laid-open
Publication No. Sho 49-97089, Japanese Patent Laid-open Publication No.
Sho 50-50487, Japanese Patent Laid-open Publication No. Sho 52-103485,
Japanese Patent Laid-open Publication No. Sho 54-26889, Japanese Patent
Laid-open Publication No. Sho 54-146285, Japanese Patent Laid-open
Publication No. Sho 56-99209, Japanese Patent Laid-open Publication No.
Sho 57-131208, Japanese Patent Laid-open Publication No. Sho 57-145106,
Japanese Patent Laid-open Publication No. Sho 58-27706, Japanese Patent
Laid-open Publication No. Sho 58-65708, Japanese Patent Laid-open
Publication No. Sho 59-133210, etc.
In another more preferred embodiment, the component A, which has the above
requirements, is such that the density is 0.860 to 0.910 g/cm.sup.3, that
the maximum fusion Peak temperature as measured by a differential scanning
calorimeter is 60.degree. to 120.degree. C., preferably 65.degree. to
115.degree. C., and that the ratio of the weight-average molecular weight
to the number-average molecular weight as measured by the GPC process is
1.5 to 3.0, preferably 1.8 to 2.8.
If the density is less than 0.860 g/cm.sup.3, the mechanical strength may
be insufficient.
If the maximum fusion peak temperature as measured by a differential
scanning calorimeter exceeds 120.degree. C., the crystalline component is
in excess so that the impact resistance at low temperature may be
insufficient.
If the ratio of the weight-average molecular weight to the number-average
molecular weight as measured by the GPC process is less than 1.5, the
processibility may be insufficient. If the ratio exceeds 3.0, on the other
hand, the mechanical strength may be insufficient.
The above preferred component A may be obtained by any process without any
restriction, for instance a high temperature-high pressure process, a gas
phase polymerization process, a slurry polymerization process, a solution
polymerization process, etc. As a usual process, mention may be made of a
process in which a metallocene type or Ziegler type catalyst at a
temperature in a range of 30.degree. to 300.degree. C. under a pressure in
a range of normal pressure to 3,000 kg/cm.sup.2 in the presence or absence
of solvent in a gas-solid, liquid-solid or homogeneous liquid phase.
The process of polymerization with the use of a metallocene type catalyst
in the presence of a hydrocarbon solvent under a pressure in a range of 1
to 30 kg/cm.sup.2, is suitable from the standpoint that an
ethylene-.alpha.-olefin copolymer having a narrower molecular weight
distribution and a narrow chemical composition distribution is obtainable
so that it is possible to realize more excellent mechanical strength.
The metallocene type catalyst is represented by a general formula
R.sup.1.sub.k R.sup.2.sub.1 R.sup.3.sub.m R.sup.4.sub.n M, wherein M
represents zirconium, titanium, hafnium or vanadium, R.sup.1 represents a
group having a cycloalkadienyl skeleton, R.sup.2 to R.sup.4 represents a
group having a cycloalkadienyl skeleton, an alkyl group, a cycloalkyl
group, an aryl group, an aralkyl group, an alkoxy group, an aryloxy group,
a halogen atom or a hydrogen atom, k and 1 represents 1 or a greater
integer, and k+1+m+n=4. Mention may be made of a catalyst composed of (i)
a transition metal compound including a ligand having a cycloalkadienyl
skeleton or (ii) a transition metal compound which includes at least two
ligands each having a cycloalkadienyl skeleton, and in which at least two
ligands having a cycloalkadienyl skeleton are each bonded via a lower
alkylene group, and (iii) an organic aluminum oxide compound.
A vanadium compound as the Ziegler type catalyst is represented by a
general formula VO(OR.sup.5).sub.p X.sub.3-p, wherein R.sup.5 represents a
hydrocarbon group, X represents a halogen atom, and p represents a number
of 0 to 3. Its examples are VOCl.sub.3, VO(OCH.sub.3)Cl.sub.2,
VO(OCH.sub.3).sub.2 Cl, VO(OCH.sub.3).sub.3, VO(OC.sub.2 H.sub.5)Cl.sub.2,
VO(OC.sub.2 H.sub.5).sub.2 Cl, VO(OC.sub.2 H.sub.5).sub.3, VO(OC.sub.3
H.sub.7)Cl.sub.2, VO(OC.sub.3 H.sub.7).sub.2 Cl, VO(OC.sub.3
H.sub.7).sub.3, VO(OisoC.sub.3 H.sub.7)Cl.sub.2, VO(OisoC.sub.3
H.sub.7).sub.2 Cl, VO(OisoC.sub.3 H.sub.7).sub.3 and mixtures of the these
compounds. With p of 0 to 1, it is possible to obtain an
ethylene-.alpha.-olefin copolymer which has a narrower molecular weight
distribution and a uniform chemical composition distribution.
Further, an organic aluminum compound as the Ziegler type catalyst is
represented by a general formula R.sup.6.sub.q AlX.sub.3-q, wherein
R.sup.6 represents a hydrocarbon group, X represents a halogen atom, and q
represents a number of 1 to 3. Its examples are (C.sub.2 H.sub.5).sub.2
AlCl, (C.sub.4 H.sub.9).sub.2 AlCl, (C.sub.6 H.sub.13).sub.2 AlCl,
(C.sub.2 H.sub.5).sub.1.5 AlCl.sub.1.5, (C.sub.4 H.sub.9).sub.1.5
AlCl.sub.1.5, (C.sub.6 H.sub.13).sub.1.5 AlCl.sub.1.5, C.sub.2 H.sub.5
AlCl.sub.2, C.sub.4 H.sub.9 AlCl.sub.2, C.sub.6 H.sub.13 AlCl.sub.2, etc.
Preferable compounds are those in which q is 1 to (C.sub.2
H.sub.5).sub.1.5 AlCl.sub.1.5 is particularly preferable.
Further, combining halogenated ester with the vanadium compound/organic
aluminum compound catalyst system permits obtaining an
ethylene-.alpha.-olefin copolymer, which has a narrower molecular weight
distribution and a narrower chemical composition distribution, and is thus
suitable for obtaining the copolymer according to the invention.
The halogenated ester is represented by a general formula R.sup.7
COOR.sup.8, wherein R.sup.7 represents an organic group obtained by
substituting halogen for some or all of the hydrogen atoms of a
hydrocarbon group with a carbon number of 1 to 20, and R.sup.8 represents
a hydrocarbon group with a carbon number of 1 to 20, and it is preferably
a compound obtained by substituting chlorine for all substituted groups in
R.sup.8, for example, perchlorocrotonate. Its examples are
ethyldichloroacetate, methyltrichloroacetate, ethyltrichloroacetate,
methyldichlorophenylacetate, ethyldichlorophenylacetate,
methylperchlorocrotonate, ethylperchlorocrotonate,
propylperchlorocrotonate, isopropylperchlorocrotonate,
phenylperchlorocrotonate, etc.
The component B according to the invention is a crystalline polypropylene
in which the melt flow rate at a temperature of 190.degree. C. and under a
load of 2.16 kg is 0.1 to 10 g per 10 min., preferably 0.2 to 8 g per 10
min. If the melt flow rate is insufficient, the processibility is
deteriorated. If the rate is excessive, the impact resistance is
deteriorated.
As the component B, mention may be made of homepolymers of propylene,
random copolymers containing propylene and 10% by weight or below of
.alpha.-olefin, which excludes propylene, such as .alpha.-olefin having a
carbon number of 2 or 4 to 10, e.g., ethylene, butene-1, pentene-1,
hexene-1, heptene-1, octene-1, nonene-1, decene-1, 4-methylpentene-1,
4-methylhexene-1, 4,4-dimethylpentene-1, etc., and block copolymers 15% by
weight or below of the above .alpha.-olefin and the like. The comonomer
which is copolymerized with propylene is usually ethylene, but random
terpolymers of ethylene-butene-propylene and block copolymers of
ethylenebutene copolymer with propylene may be preferable.
The component B may be obtained by any method without any restriction, and
it is possible to adopt any well-known method.
The resin composition according to the invention is composed of 5 to 30% by
weight, preferably 5 to 20% by weight, of the component A and 95 to 70% by
weight, preferably 80 to 95% by weight, of the component B. If the
component A is insufficient (i.e., if the component B is excessive), the
impact resistance at low temperature is inferior. If the component A is
excessive (i.e., if the component B is insufficient), on the other hand,
the chipping resistance and the mechanical strength are inferior.
The resin composition with the components A and B mixed in the above ranges
according to the invention is suitably such that the melt flow rate at
190.degree. C. is 0.05 to 10 g per 10 min. If the melt flow rate is
insufficient, the fluidity of the material at the time of forming
"processing" may be inferior. If the rate is excessive, on the other hand,
the processibility of coating a tubular base may be inferior.
The resin composition according to the invention may be obtained by such
method as mixing the components A and B by the usual mixing operation,
such as a Banbury mixer process, an extrusion granulating process, etc. In
this case, in addition to the components A and B, such additives as a
neutralizing agent, an antioxidant, a weather-ability improving agent, an
antistatic agent, a pigment, etc. may be added thereto in a range free
from impeding the effects of the invention.
The resin-coated pipe according to the invention is obtainable by extrusion
coating a tubular base with the above resin composition.
The tubular base is not particularly limited, and it is possible to use
various metal pipes such as steel pipes, copper pipes, aluminum pipes,
etc. Among these pipes, steel pipes are preferred. The shape of the pipe
is not particularly limited, and the invention is applicable to straight
pipes, bent pipes, etc. Further, the sectional profile of the pipe may be
circular, polygonal, etc. Further, the surface of the pipe may be treated
with fluorine resin coating or the like. Furthermore, the diameter of the
pipe is not particularly limited, that is, it is possible to use pipes of
various sizes. For example, the invention is applicable to such thin pipes
as 10 mm or below in diameter.
As a method of extrusion coating a straight tubular base with the resin
composition, for instance, one using crosshead dies for extrusion coating
is excellent in view of the mass production and is thus preferable. This
method permits continuously coating the entire pipe length, thus
revolutionally improving the productivity and attaining energy saving.
The thickness of the resin coating is not particularly limited, but it is
usually about 0.3 to 2 mm.
The extruder may be those which are used for usual extrusion granulation.
The extrusion capacity of the extruder may be considered in dependence on
the diameter of the pipe to be coated and the aiming thickness of the
coating. As for the extruding conditions, the temperature setting for the
usual extrusion granulation is sufficient, and it is possible to obtain
resin-coated pipes with various coating thickness by adjusting the amount
of the extruded resin according to the diameter of the pipe to be coated,
process line speed and aiming coating thickness. Further, the obtained
resin-coated pipe may be subjected to, for instance, a bending process, as
secondary process.
As described in the foregoing, according to the invention, by using a resin
composition excellent in processibility it is possible to provide a
resin-coated pipe which is excellent in the mechanical strength, normal
and low temperature impact resistance, heat resistance, chipping
resistance and coating surface appearance.
EXAMPLES
The following examples are given for the purpose of illustration of this
invention and are not intended as limitations thereof.
The following measurement and evaluation methods were adopted.
(1) Melt flow rate (MFR)
The measurement was made at 190.degree. C. and under a load of 2.16 kg in
conformity to JIS K7210.
(2) Density
A test piece was prepared in conformity to JIS K6760 and conditioned at
23.degree. C. for one day without annealing. Then, the measurement was
made.
(3) Maximum fusion peak temperature as measured with a differential
scanning calorimeter
Using a "Parkinelmer 7" type DSC, the maximum fusion peak temperature was
measured in conformity to JIS K7121. The test piece was conditioned in
conformity to 3-(2) of JIS K7121.
(4) number-average molecular weight M.sub.n and weight-average molecular
weight M.sub.w
Using a GPC measuring instrument manufactured by WATERS Inc., the average
molecular weights were obtained in terms of polystyrene values.
(5) Stiffness (mechanical strength)
A test piece was cut out of a pressed sheet 1 mm in thickness. Measurement
was made in conformity to ASTM D747.
(6) Low temperature shock test (low temperature impact resistance)
Using a high rate impact tester manufactured by Reometrix Inc., a
sheet-like test piece 1 mm in thickness conditioned at -30.degree. C. for
3 hr. was tested to evaluate the break-down state.
(7) Flying stone test (chipping resistance)
Using a gravelometer manufactured by Suga Tester Co., Ltd., the measurement
was made in conformity JASO M104.
(8) Coating surface appearance
After the extrusion coating, the surface was visually evaluated as follows.
.circleincircle. . . . excellent, .largecircle. . . . good, .times. . . .
bad
EXAMPLES 1 TO 5 AND COMPARATIVE EXAMPLES 1 TO 4
Resin-coated steel pipes were obtained by extrusion coating a tubular base
with the compositions shown in Tables 1 and 2 using a extruder 30 mm in
diameter with crosshead dies (i.e., non-bent uniaxial horizontal extruder
manufactured by Union Plastics Inc.) under the conditions of a die
temperature of 260.degree. C., a processing line speed of 4.0 m/min., a
steel pipe outer diameter of 8.0 mm and a coating thickness of 0.5 mm. The
conditions and evaluation results are shown in Tables 1 to 4.
It is known from the above results that the Examples which meet the
conditions according to the invention show satisfactory results in all the
evaluation items. On the other hand, in Comparative Example 1 not using
the component A, the low temperature impact resistance, low temperature
chipping resistance and coating surface appearance were all inferior. In
Comparative Example 2 only using the component A having a too high density
without using the Component B, the stiffness and normal and low
temperature chipping resistance were inferior. In Comparative Example 3,
in which the density of the component A was too high, the low temperature
impact resistance and low temperature chipping resistance were inferior.
In Comparative Example 4, in which the component A was excessive (i.e.,
the component B was insufficient), the normal and low temperature chipping
resistance and coating surface appearance were inferior.
TABLE 1
______________________________________
Examples 1 2 3 4 5
______________________________________
Component A
Kind *1 A1 A1 A2 A2 A3
Properties
MFR(g per 10 min.)
0.90 0.90 0.60 0.60 2.0
Density
(g/cm.sup.3) 0.908 0.908 0.885 0.885 0.905
Max. fusion
peak temp. (.degree.C.)
115 115 65 65 92
Mn .times. 10,000
11 11 12 12 9.6
M.sub.w /M.sub.n
4.0 4.0 2.0 2.0 2.0
Amount (wt. %)
20 10 10 20 10
Component B
Kind *2 B1 B1 B1 B1 B1
Properties
MFR(g per 10 min.)
0.40 0.40 0.40 0.40 0.40
Amount (wt. %)
80 90 90 80 90
MFR of components
0.45 0.40 0.41 0.43 0.47
A and B *3
(g per 10 min.)
______________________________________
TABLE 2
______________________________________
Comparative
Examples 1 2 3 4
______________________________________
Component A
Kind *1 -- A4 A5 A2
Properties
MFR (g per 10 min.)
-- 0.80 0.80 0.60
Density (g/cm.sup.3)
-- 0.921 0.919 0.885
Max. fusion -- 120 115 65
peak temp. (.degree.C.)
Mn .times. 10,000
-- 11 11 12
M.sub.w /M.sub.n
-- 11 4.0 2.0
Amount (wt. %)
0 100 10 40
Component B
Kind *2 B1 -- B1 B1
Properties
MFR (g per 10 min.)
0.40 -- 0.40 0.40
Amount (wt. %)
100 0 90 60
MFR of components
0.40 0.80 0.43 0.47
A and B *3
(g per 10 min.)
______________________________________
TABLE 3
______________________________________
Examples 1 2 3 4 5
______________________________________
Evaluation
Stiffness 6,300 7,600 7,500 7,000 8,000
(kg/cm.sup.2)
Low temperature
ductile ductile ductile
ductile
ductile
impact test
(-30.degree. C.)
Flying stone test
+23.degree. C.
.largecircle.
.largecircle.
.circleincircle.
.largecircle.
.circleincircle.
-30.degree. C.
.largecircle.
.largecircle.
.largecircle.
.circleincircle.
.largecircle.
Coating surface
.circleincircle.
.largecircle.
.circleincircle.
.circleincircle.
.circleincircle.
appearance
______________________________________
TABLE 4
______________________________________
Comparative Examples
1 2 3 4
______________________________________
Evaluation
Stiffness 9,300 2,300 9,000 4,500
(kg/cm.sup.2)
Low temperature
brittle ductile brittle
ductile
impact test (-30.degree. C.)
Flying stone test
+23.degree. C. .largecircle.
X .largecircle.
X
-30.degree. C. X X X X
Coating surface
X .largecircle.
.largecircle.
X
appearance
______________________________________
*1 Kind of component A:
A1: Ethylene-butene-1 copolymer (butene-1 content: 11 wt. %, prepared by
high pressure bulk process under a polymerization pressure of 1,000
kg/cm.sup.2 and at a polymerization temperature of 200.degree. C.)
A2: ethylene-butene-1 copolymer (butene-1 content: 18 wt. %)
A3: ethylene-butene-1 copolymer (butene-1 content: 10 wt. %)
A4: ethylene-butene-1 copolymer (butene-1 content: 7 wt. %, provided by
Mitsubishi Yuka Co., Ltd., straight chain low density polyethylene "UE320"
(a trade name))
A5: ethylene-butene-1 copolymer (butene-1 content: 7 wt. %)
*2 Kind of component B:
B1: crystalline ethylene-propylene block copolymer (ethylene content: 6 wt.
%)
*3 MFR of components A and B
Melt flow rate of the mixture of the components A and B
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